AIMS/HYPOTHESIS:

This study was carried out to determine the impact of American Diabetes Association (ADA) 2000 criteria for the diagnosis of gestational diabetes mellitus (GDM) in the Spanish population.

METHODS:

Pregnant women were assigned to one of four categories: negative screenees, false-positive screenees, ADA-only-GDM (untreated) and GDM according to National Diabetes Data Group (NDDG) criteria (treated). Fetal macrosomia and Caesarean section were defined as primary outcomes, with seven additional secondary outcomes.

RESULTS:

Of 9,270 pregnant women screened for GDM, 819 (8.8%) met NDDG criteria. If the threshold for defining GDM had been lowered to ADA criteria, an additional 2.8% of women would have been defined as having the condition (relative increase of 31.8%). Maternal characteristics of women with ADA-only-GDM were between those of false-positive screenees and women with NDDG-GDM. The risk of diabetes-associated complications was slightly elevated in the individuals who would have been classified as abnormal only after the adoption of ADA criteria. In addition, the ADA-only-GDM contribution to morbidity was lower than that of other variables, especially BMI.

CONCLUSIONS/INTERPRETATION:

Use of the ADA criteria to identify GDM would result in a 31.8% increase in prevalence compared with NDDG criteria. However, as the contribution of these additionally diagnosed cases to adverse GDM outcomes is not substantial, a change in diagnostic criteria is not warranted in our setting.